Sharpening device for sewing machine trimming appliance



Sept. 3, 1963 M. BROUGH 3,102,373

SHARPENING DEVICE FOR SEWING MACHINE TRIMMING APPLIANCE Filed NOV. 21, 1960 United States Patent 3,102,373 SI-IARPENING DEVICE FOR SEWING MACEHNE TRIMMlNG APPLIANCE Morris Brough, 36 Wellhouse Drive, Leeds 8, York County, England Filed Nov. 21, 1960, Sen No. 70,687 2 Claims. (Cl. 51-246) The invention relates to trimming or paring appliances for sewing machines and has as its object the provision of a new or improved trimming appliance which may serve either as an attachment to existing sewing machines of certain types or may be included in the make-up of new sewing machines to form a composite trimming or paring and sewing machine.

In the tailoring trade for instance, after a sleeve is inserted into a garment such as a jacket or coat, the shoulder pad and wedding have to be sewn into the armholes, there being machines which will perform this sewing in one operation.

There is another operation to be effected before the armhole is completed which consists in trimming the canvas linings and wedding projecting from the armhole in order that the same may conform to or align with the armhole in the cloth. This trimming operation is usually performed by a machine which traverses the material in a similar manner to a sewing machine and is provided with a knife or guillotine which severs the surplus linings and paddings with a reciprocatory or chopping action. Such knives require frequent changes for sharpening.

Broadly, the trimming or paring appliance of the present invention comprises a power-driven circular cutter or knife, intended for mounting in proximity to the customary sewing or needle mechanism of a sewing machine, and means for automatically sharpening the said knife, thereby obviating stoppages for servicing.

By ensuring that the sharpening of the cutter is automatically effected, machine operators are relieved of trouble and responsibility so far as sharpening is concerned, but it must be understood that independent means may be incorporated in the make-up of the appliance whereby an operator may augment the automatic control and enable additional sharpening operations to the effected at will and for so long as is considered necessary.

In its most simple form the paring appliance includes a power-driven knife and at least one abrasive disc or member which disc or member is adapted to 'be automatically and intermittently engaged with and disengaged from the cutting edge of the said knife. If desired an additional abrasive member may be provided, and manually controllable means may be included in the appliance for effecting sharpening at the will of an operator.

Several ways of carrying the invention into effect may be employed and in order that the invention may be thoroughly comprehended diagrammatic drawings are hereto appended, in which:

FIGURE 1 is a front View of a trimming or paring appliance and combined knife sharpening means according to the invention.

FIGURE 2 is a partly sectional detail view of a fragmental part of the gear-box of FIGURE 1, illustrating one method of automatically actuating the sharpening means according to the invention.

The trimming or paring appliance is constructed so as to be capable of being mounted upon a suitable sewing machine S driven by electromotor in conventional manner.

An additional or independent electromotor 1 forms part of the appliance and by means of an appropriate gear box 2 drives a horizontal shaft 3 supported in a bearing in the gear-box casing. The outer end of the shaft 3 is universally coupled or articulated 'by link 4 Faten'ted Sept. 3, 1963 ice a detachable circular cutter, trimming or paring knife 7 located in close proximity to the sewing or needle mechanism of the sewing machine.

At a suitable distance from the shaft 3 and prefei'ably parallel thereto a further spring-loaded shaft 8 is reciprocably mounted in hearings to the gear-box casing. The outer end of the shaft 8 is linked or articulated by slotted member 10 to one end of a lever 11 pivoted upon the hearing bracket 6. -Rotatably mounted upon the other end of the lever 11 is a primary circular abrasive wheel or grinding disc 12 adapted to co-act with the cutting edge of the knife 7.

A small diameter secondary grinding disc 13, which is preferably. spring-biased towards the disc .12, may be mounted upon the sewing machine at the side of the knife remote from the said disc.

Means are provided in the gear-box 2 for automatically reciprocating the shaft 8. One method of achieving the reciprocating motion is to mount a vertical shaft 14 within the gear box and to arrange for the shaft to be suitably driven by the motor 1. Then by providing a suitably contoured cam 15 upon the shaft 14 in a position to register with the inner end of the shaft 8 which is biased in one direction by the spring 16 rotation of the vertical shaft 14 causes the cam 15 to actuate the shaft 8 to and fro. Consequently, the pivoted lever 11 is partially rotated in first one direction and then the other for the grinding disc 12 to intermittently engage and disengage with the cutting edge of the knife to intermittently sharpen the same. Tension of the spring 16 on shaft 8 may be adjusted by member 17 if desired for varying the pressure exerted by the disc 12 on the knife 7.

It will therefore be understood that the sharpen-ing operation automatically and intermittently takes place whencver the machine is operating, the small diameter abrasive disc 13 serving to remove any arris or uneveness which may develop at the edge of the trimming knife.

If desired, manually operated means may be included in the make-up of the appliance for retaining the grinding disc 12 in engagement with the trimming knife independently of the automatic means. This may be necessary in the occasional event of the automatic sharpening periods being insuficiently prolonged and may be very simply effected by manually operating the disc 12 against the knife 7 by means of the spring-loaded rod 9. A light spring 18 is provided to hold the disc 12 off the knife when the manual sharpening effect is not functioning and the slot in the member 10 enables the said member 10 to continue its reciprocations irrespective of the manually held positions of the lever 11.

In this manner and by the hereto-fore described means combined sewing and trimming operations of the kind already stated may be simultaneously effected without stoppages for knife sharpening.

It will readily be understood that any suitable wellknown means such as sprockets, worm and worm wheel mechanism bevel gears or a combination thereof may be provided in the gear-box 2 for transmitting appropriate drive from the motor 1 to the shafts 3 and 14. Also, that refinements such as lubricating means, covers and guards are included where necessary.

Although rotatable grinding or abrasive discs have been mentioned, it must be understood that other types of grindstones or the like abrasive-members would be utilised.

the said knife.

-with said circular knife, an

I claim:

1. A sharpening device for a circular sewing machine cutting knife comprising a support along a side of the knife, a pivo-tally mounted lever on said support to bring a sharpening wheel at one end thereof into engagement abrasive sharpening wheel mounted at said end of said lever for reciprocating movement toward and away from the knife, automatic reciprocating means to move said sharpening wheel into and out of engagement with said cutting knife including cam and spring means connected to a slotted members which is connected at one end to said lever, and a secondary abrasive member located on the side of said knife remote from said sharpening wheel, said secondary abrasive References Cited in the file of this patent UNITED STATES PATENTS Lefkowitz Apr. 22, 1924 Gage Mar. 31, 1959 

1. A SHARPENING DEVICE FOR A CIRCULAR SEWING MACHINE CUTTING KNIFE COMPRISING A SUPPORT ALONG A SIDE OF THE KNIFE, A PIVOTALLY MOUNTED LEVER ON SAID SUPPORT TO BRING A SHARPENING WHEEL AT ONE END THEREOF INTO ENGAGEMENT WITH SAID CIRCULAR KNIFE, AN ABRASIVE SHARPENING WHEEL MOUNTED AT SAID END OF SAID LEVER FOR RECIPROCATING MOVEMENT TOWARD AND AWAY FROM THE KNIFE, AUTOMATIC RECIPROCATING MEANS TO MOVE SAID SHARPENING WHEEL INTO AND OUT OF ENGAGEMENT WITH SAID CUTTING KNIFE INCLUDING CAM AND SPRING MEANS CONNECTED TO A SLOTTED MEMBERS WHICH IS CONNECTED AT ONE END TO SAID LEVER, AND A SECONDARY ABRASIVE MEMBER LOCATED ON THE SIDE OF SAID KNIFE REMOTE FROM SAID SHARPENING WHEEL, SAID SECONDARY ABRASIVE MEMBER BEING SPRING BIASED TOWARDS SAID KNIFE TO PRODUCE A FINE EDGE ON SAID KNIFE. 